Edwin Thompson Denig was assigned as the post bookkeeper at Fort Union on the Upper Missouri in 1837 by the American Fur Company. He spent close to two decades there and married into the Assiniboine. In the summer of 1851, Father Pierre Jean de Smet spent two weeks at Fort Union. He encouraged Denig to write a number of sketches of the manners and customs of the Assiniboine and neighboring tribes. Denig compiled additional information in response to queries by early ethnographers, including Henry Rowe Schoolcraft, who were collecting ethnological information about Indian tribes in the United States.